Introduction
Sensitization to pollen plays a crucial role in the development of
allergic disorder,1 which has been reported to lead to
more serious allergic symptoms and to increase the risk of
asthma.2-3. An interaction between the exposure to
pollen and being sensitized to pollen allergens was detected that the
effect was less pronounced in individuals who were sensitized to only
one type of pollen, compared with who are sensitized to all types of
pollen. Furthermore, as different pollen types are released at different
periods of the pollen season, atopic individual sensitized to more than
one type of pollen are experiencing a longer period of exposure, which
may lead to a stronger effect on airway hyperreactivity and reduced lung
function.4
Pollen season is related to the flowering season, for pollen has to be
previously produced and emitted by mature flowers. Weather variables,
mainly air temperature, sunshine and rainfall, together with
CO2 are among the main factors affecting phenology and
pollen production by plant.
The weather may be the most crucial factor because it can alter the
starting and ending of pollination and affect the change of pollen
season directly although there are several environmental factors such as
greenhouse gases, the other air pollutants. Weather conditions may
subsequently influence the occurrence of allergic diseases such as
asthma, allergic rhinitis. A growing number of people are contracting
allergic diseases caused by pollen because of weather change in the
world.5
The start and end of the pollen season itself, as defined by airborne
pollen, may be influenced by factors affecting pollen dispersal, and may
not coincide exactly with the maturation of the flowers. Longer pollen
season and larger the amount of atmospheric pollen could enhance the
human exposure to allergic pollens. These might relate with an increase
in allergic sensitization. As the sensitization rate to pollen has
increased in children recently, allergic plants which is rapidly
proliferating, has emerged as a dangerous element to allergic children.
It is now essential to survey pollens around the patient for the
management of pollen allergy.6-8
A number of studies on the climate change effects on allergenic pollen
distribution have focused on analyses of observed pollen counts and
their regression relationships with local meteorological factors.
Ongoing climate change, through rising the concentration of atmospheric
CO2 and temperatures, contribute to extension of
seasonal duration and increase in multiple pollen
load.8 In an experimental study, warming and changes
in CO2 were demonstrated an increase in pollen
production.9,10 Elevated CO2concentrations resulted in early pollen production from trees and
greater seasonal pollen production.11,12 In addition,
weather patterns influence the movement and dispersion of all
aeroallergens in the atmosphere through the action of winds, rainfall
and depending on the atmospheric stability.
This study investigated the reasons for recent rising pollen allergy and
the sensitization rate to pollen has increased in children recently, and
the relationships between the changes in start and end dates of
pollination and weather changes for the past 22 years in Seoul
metropolitan area. The results of the analysis are used in an attempt to
predict trends in start dates in future. This study has important
implications for the use of phenology as an indicator of weather changes
and also for recent rising pollen allergy in children in Korea.